The TAS600 is the one with
far more installs, obviously. I don't think there is a lot of Garmin experience around.
The 600 does work pretty well.
Remember that TCAS is a big install - reckon on it taking 3-4 weeks, with the whole plane interior being stripped out, existing aerials relocated and rewired (hopefully properly), etc. Only the best avionics shops should be trusted with this job, which is why I haven't got one - could not stand the risk and the downtime, and I have too many aerials already.
Whether it is worth the money is an old argument. The UK has not had any mid-airs in IMC since WW2 and its GA traffic density is probably 10x to 100x greater than Poland. At low levels, here, much of the traffic is nontransponding anyway and I am sure the same pattern will be seen everywhere because the kinds of pilots who like to fly low are generally the kind who dislike transponding. I have decided to save the money and fly high (above 3000ft
).